Fluid control devices include various categories of equipment including control valves and regulators. Such control devices are adapted to be coupled within a fluid process control system such as chemical treatment systems, natural gas delivery systems, etc., for controlling the flow of a fluid therethrough. Each control device defines a fluid flow-path and includes a control member for adjusting a dimension of the flow-path. For example, FIG. 1 depicts a known regulator assembly 10 including a valve body 12 and an actuator 14. The valve body 12 defines a flow-path 16 and includes a throat 18. In FIG. 1, the regulator assembly 10 is configured in a flow-up configuration. The actuator 14 includes an upper actuator casing 20, a lower actuator casing 22, and a control member assembly 24. The control member assembly 24 is disposed within the upper and lower actuator casings 20, 22 and is adapted for bi-directional displacement in response to changes in pressure across the regulator assembly 10. So configured, the control member assembly 24 controls the flow of fluid through the throat 18. Additionally, as is depicted, the regulator assembly 10 includes a seat ring 26 disposed in the throat 18 of the valve body 12. When the outlet pressure of the valve body 12 is high, a sealing surface 28 of the control member assembly 24 may sealingly engage the seat ring 26 and close the throat 18. This prevents the flow of fluid through the regulator 10.
The seat ring 26 depicted in FIG. 1 further includes a rounded or tapered surface 27. The rounded or tapered surface 27 serves to streamline the flow of the fluid through an orifice 29. As fluid flows through the valve body 12, it flows from the left of the valve body 12, as depicted in FIG. 1 and up through the throat 18 via the orifice 32 in the seat ring 26. Then, the fluid deflects off a lower surface of the control member 24 including the sealing surface 28, and out to the right of the valve body 12 of FIG. 1.
FIG. 1 depicts the regulator assembly 10 equipped with one known control member assembly 24. As mentioned, and in general, the control member assembly 24 includes the sealing surface 28 that is adapted to be engaged by a seating surface 31 of the seat ring 26 when the control member assembly 24 is in a closed position, preventing the fluid from flowing through the valve body 12. More specifically, the control member assembly 24 further includes a tubular member 30 and a mounting subassembly 32. The tubular member 30 includes an upper end 30a and a lower end 30b that is open and accommodates the mounting subassembly 32. The mounting subassembly 32 further includes a mounting member 34, a plug or a disk holder 36 and a sealing disk 38 having the sealing surface 28. The mounting member 34 includes a generally cylindrical body threaded into the open lower end 30b of the tubular member 30 and defining at least one through-bore 39. The disk holder 36 also includes a generally cylindrical body 37 (FIG. 3) that is fixed to the mounting member 34 with a fastener 40. In the form illustrated, the fastener 40 includes a threaded fastener. Similar to the mounting member 34, the disk holder 36 also includes at least one through-bore 41 that is axially aligned with the at least one through-bore 39 of the mounting member 34. In addition, the at least one through-bore 39 of the mounting member 34 has a diameter substantially identical to the at least one through-bore 41 of the disk holder 36.
Referring now to FIGS. 2 and 3, respectively, a top view and a cross-sectional view of the disk holder 36 of the mounting subassembly 32 FIG. 1 taken along the line A-A of FIG. 2 are depicted. As illustrated therein, the plug or disk holder 36 includes the cylindrical body 37 having a flange 42 extending radially therefrom. The flange 42 includes a top surface 44 that abuts a bottom surface of the mounting member 34 (FIG. 1) and a bottom surface 46 that includes an annular recess 48 for receiving the sealing disk 38 having the sealing surface 28. The sealing disk 38 may include a generally ring-shaped disk made of resilient material, such as polyurethane, and may be fixed or bonded to the disk holder (or plug) 36 with an adhesive, for example.
Currently cast polyurethane sealing disks 38, however, often lack sufficient bonding strength at high pressure drops and low flows, resulting in bonding failure between the disk holder 36 and the sealing disk 38, and, therefore, failure of the sealing disk 38 and the control member assembly 24 in general. As such, the performance of the regulator 10 is compromised. While other methods to secure the sealing disk 38 to the disk holder 36 or plug include mechanical methods, such mechanical methods includes a more complicated design, and, therefore, more complex manufacturing issues and increased costs.